thymus atrophy thymus medulla atrophy atrophic thymic medulla atrophic thymus medulla thymic medulla atrophy acquired diminution of the inner area of thymus lobules associated with wasting as from death and reabsorption of cells, diminished cellular proliferation, decreased cellular volume, pressure, ischemia, malnutrition, reduced function or malfunction, or hormonal changes MP:0013586 small thymus medulla medulla of thymus atrophy